I originally had this in the electrical section, then realized it would be better over here (no one responded in that area, either)....

When I did the 383 swap a week ago I found a problem with the secondary fan switch electrical connection. The sensor, which mounts in the passenger side head between #6 and #8, is VERY close to the headers on the harness end where the wires come out of the connector. So close, I cannot see how to get the electrical connector onto the sensor without dropping the headers off the passenger side. Looking closer at the connector, it show evidence of getting really hot in the past even with the factory exhaust manifolds (it's all discolored and looks brittle, but not quite hot enough to have melted any). Using this type sensor and wiring will definitely not last with the headers.

This connector is not the button-ended kind like is on the other side of the engine that drives the temperature guage. This connector has the rounded pin type connector that requires a male connector on the harness to plug into it (and sticks out a lot farther than the button ended type). There is also a splice in the harness where it looks like this connector has been replaced at least once in the past.

It is my understanding that this sensor's only function is to control when the second electric fan kicks on. That appears true as well since so far all I've seen running is one of the two factory electric fans.

So what are my options? It gets hot enough in Dallas, TX, that I know I'm going to need that second fan running before too much longer.

1. Do the 91 Formula's normally use this type of sensor, or did someone swap to this style in the past?
2. Can a button-ended type sensor be substituted for the plug-in type and still work properly? Can someone give me a part number for this"
3. Should I consider splicing the second fan into the primary fan's circuit so that any time the primary comes on the secondary doea as well?
4. If I do option #3, how would I go about doing this?

Sure hope someone can give me a hand on this....

Have a Great Day!!!

- Vern

 

Come on folks, surely someone else has had a problem like this where they installed headers on a 3rd Gen that has dual electric fans and then didn't have clearance on the secondary fan switch. What did you do? Please help me out here.....


- Vern

 

Honestly, I would just wire the fans both on one circuit and use one sensor. Cooling the whole radiator at once should work a lot better than cooling only half of it.

 

Well, I relocated my secondary fan switch to the front of my SDPC vortec TPI base (there was an extra port for the cold start temp switch, same threads as the fan switch, so perfect!!)... The wire could be removed from the harness easily to route it there too, worked real good; would take about 5 minutes to switch it out now and it looks like a factory setup... Also, I went with a different switch because the stock secondary fan switch comes on at something like 238* or something equally crazy!! You might try a FS1 fan switch (GP Sorensen number, you can get it at Advance Auto Parts), I believe it closes the switch at like 220* or maybe a little lower (ask them to look it up in the GP Sorensen Illustrated Parts Guide, it has the specifications listed there).. That switch also has the same connector so its a direct plug-and-play setup.

Oh, and to reassure you that you're not the only one, the connector on my GTA when I got it was broken and brittle (the top of the switch broke off, then the rest crumbled when I tried to take it out of the connector).. What amuses me is that I have reciepts of several different shops the previous owner took it to to try to fix it.. At least I got the new relays and two new fan motors out of it (they never did realize that the controlling switch is back there, )...

Hope that wasn't too much to read...

 

Thanks for the input, folks. I'm looking at three alternatives right now: Willie's "total fan control" idea, replacing the current switch with one that comes on at 180-190 degrees (and I love the idea of relocating it, I think my LPE SuperRam intake has an extra port on the front similar to thirdgen88's SDPC intake!), and trying to figure out how to wire them to come on at the same time like TA5LiterHO suggested so the PROM can totally control the on and off temps.

If I could figure out how to easily combine them without overloading the existing circuitry that would probably be my first choice, that way I'd be able to control both via the computer. If I can't figure that out I'll probably go with a lower temp switch, probably relocated up next to the primary fan switch.

Again, thanks for the replies, and any suggestions on how to do combine the relay wiring to run both fans any time the primary comes on would be appreciated.

Have a Great Day!!!


- Vern

 

Vern:
Do it like Thirdgen88 says, it works great and no hassle (use the 185 temp switch tho).

 

Any suggested part numbers for that 185 degree fan switch? Where to get it? (It's getting warm here in Dallas and I'd rather not have to wait for a shipment from Summit). That does sound like a good idea, Don, Thanks!

Have a Great Day!

- Vern